The present invention relates generally to telecommunication systems comprising a plurality of communication networks through which a user can roam, such as a mobile or cordless telecommunication user, and more particularly to a method of and a telecommunication system equipped for providing a consistent set of services to a user when roaming through the networks of a system.
Typical cordless radio communication networks such as operating in accordance with the Digital Enhanced Cordless Telecommunications (DECT) standard, generally comprise a plurality of radio base stations which connect to a so-called central interface unit or radio exchange which, in turn, is connected to or integral with a Private Branch Exchange (PBX). Each base station covers a limited area, generally called a cell, within which a wireless communication link can be established with a remote telecommunication device such as a portable radio telephone. A call in progress can be handed over from one base station to another while the remote telecommunication device is moving in the coverage area of the radio network.
A plurality of cordless radio communication networks, such as networks installed at geographically spread sites of a company or public radio networks each covering a particular city, for example, may form a radio telecommunication system to which a user may have acquired access rights. The several networks of a system may operate in a so-called stand-alone or in a mutually interconnected configuration. In the latter case using the Public Switched Telephone Network (PSTN) or private or leased lines for the coupling of the networks, for example.
Despite the current approach for open or generic communication protocols and interfaces, the different telecommunication devices and/or the networks obtained from different manufacturers may still require different access procedures and protocols for accessing network services, for example.
Services like diverting a call to a user or closing off the divert function may, in different networks, require different commands from the telecommunication device. For example, a service like Call Back (CB) may in one network be initiated by dialing a xe2x80x9c5xe2x80x9d, for example, whereas this service is accessed in another network by dialing a xe2x80x9c3xe2x80x9d or is not available at all. Without any additional support from the system, a user roaming through the several networks has to posses the relevant knowledge of how to access the different services in the different networks. From a service point of view, this is not a user friendly solution.
Short number dialing is an example of a service which, in general, has a limited use. For instance, in a first network the subscribers thereof may be accessed by a three digit telephone number which can be stored in a memory of a telecommunication device. However, using the same device in a second network, for instance a network at a different site of a company, the short numbers that are stored in the telecommunication device cannot be used as these numbers refer now to the subscribers of the second network or even to non-existing subscribers in the second network. Thus, in order to set up a call, the stored numbers need to be preceded by suitable access codes or prefixes, such as access codes for getting connected to an external line, area codes etc. which can be different for and from each individual network and, accordingly, have to be known by the user of the telecommunication device.
Further, in the case of services such a Call Forwarding on No Reply (CFNRy) or Call Forwarding on Busy (CFB), a user may have stored in a database of the communication systemxe2x80x94such as a database located at the home network of the userxe2x80x94a plurality of extension numbers to which incoming calls have to be forwarded. The home network of a user is in general the network at which subscriber specific information of a user is registered such as access rights, information for billing purposes, etc.
When roaming to a different (visited) network, these data are not known to this network and, in the case of a telecommunication system having interconnected networks, the relevant data have to be transferred by the telecommunication system from the home network database to the visited network database whenever the user is registered at a visited network, for example. In another embodiment the visited network has to set up inquiry calls to the home network to fetch the relevant data on a case by case basis, for example. However, the network features or the network support for establishing such data transfers or inquiry calls, for example, are not yet generally available whereas also a considerable amount of signaling load is imposed on the telecommunication system in those cases wherein such network features are already available.
German patent application DE 43 43 335 discloses a multi mode radio telephone terminal (GSM/DECT) which, among others, provides the user with a network independent interface for call set up. The radio telephone is provided with means for establishing the network to which the radio telephone is currently connected and means for storing a complete subscriber number, i.e. area code, local prefix and terminal number of a preferred network, for example the network at which the user is available during business hours. The radio telephone is further provided with means for processing a dialled telephone number.
Independent of the network to which the radio telephone currently connects, the user may dial a telephone number in accordance with the interface of the preferred network. A dialled telephone number is processed in accordance with the stored subscriber number and call set up information of the network to which the radio telephone currently connects. Accordingly, the user can place calls from the radio telephone terminal without having knowledge of call set up procedures different from his preferred network or home network. That is, the user is provided with a universal user interface for call set up.
British patent application 2,292,047 discloses a radio telephone having different software modules bearing software such that services can be executed from the radio telephone in at least two different networks having different service software requirements. This British patent application is not concerned with the above described problem of providing a user interface independent of the network to which a radio telephone currently connects.
Both, DE 43 43 335 and GB 2,92,047 disclose a fixed storage of service specific data when the radio telephone is used for the first time.
The present invention has for its object to provide in a cost effective, flexible and efficient manner a consistent set of services, inclusive call set up, to a telecommunication user roaming in or between networks of a telecommunication system. In particular to provide the set of services to the user in a uniform manner such that, while roaming through different networks, the user does not have to possess the knowledge of how to access the different services in the different networks.
The present invention has also for its object to provide a telecommunication device and a telecommunication system equipped for providing a consistent set of services to a user when roaming through different networks of a-telecommunication system. In particular a radio telecommunication device by which a user may access different radio communication networks, such that while roaming from one network to another the user can access the different services of a system in a consistent manner by using one and the same telecommunication device. For example, a cordless telephone operating in accordance with the DECT standard.
According to the invention there is provided in a telecommunication system including a plurality of communication networks a method of providing a user with a consistent set of services when roaming through the networks using a telecommunication device having memory means for storing data specific to services of the telecommunication system. The method comprises the steps of:
exchanging service specific data between the telecommunication device and a communication network when accessing the communication network and/or a particular service, and
processing the exchanged data, such to provide services to the user in accordance with the service specific data.
Following the invention, data relating to services available in the telecommunication system are stored in the telecommunication device, such as a radio telephone terminal, and the telecommunication networks. Accordingly, when roaming in or between the several networks of a telecommunication system the relevant data for accessing or completing a service can be directly exchanged between the telecommunication device and a communication network. Thereby providing a flexibel system, not limited to predifined user data and network data such as the prior art systems disclosed above and eliminating the need for significant system data transfers and, accordingly, delays when retrieving data from a home database or a central system database, for example.
Such service specific data may contain, for example, subscriber numbers to which an incoming call has to be diverted when the telecommunication device is busy or when the user has switched the device into a non-disturbance mode, for example. Further, the service specific data may comprise access codes for accessing services in the different networks, prefix codes in the case of a short number service, etc.
In an embodiment of the method according to the invention, at least part of the user specific data is exchanged over a transmission path established between the telecommunication device and the network, and the retrieved data are stored in memory means of the network.
Service specific data may be exchanged with a telecommunication device after or in the course of its registration at a network following a registration procedure when the device is put into operation, for example. The exchanged data may be temporarily stored in the memory means of the network and/or the telecommunication device, at least for the duration of providing service to the telecommunication device. The service specific data may be completely downloaded by the network or on a service-by-service basis, for example.
In an embodiment of the method according to the invention, the service specific data are stored in the memory means of the telecommunication device relative to data identifying a particular network or a group of networks.
Accordingly, the network may retrieve only those service specific data which refer to the particular network or services of the network. This provides a very efficient data transfer and storage because data relevant to several networks may be commonly stored in a telecommunication device under the same heading, for example.
In another embodiment of the invention, at least part of the service specific data is retrieved and processed by the telecommunication device. That is, relative to the data identifying a network or a group of networks, for example, when accessing a particular service the telecommunication device retrieves and processes such service specific data required for completing the service.
The service specific data stored in the memory means of the telecommunication device may be restricted to those services available to the user of the particular device. Accordingly, access from a particular telecommunication device to services for which no access rights have been acquired can be effectively prevented.
In yet another embodiment of the invention the service specific data in the memory means of the telecommunication device may contain or may be stored relative to data corresponding to service access rights indicating the services which are available to a user. In such embodiment, service specific data are retrieved and/or processed in accordance with these service access rights. In general, the user of a telecommunication device is only allowed to have access to those services to which access rights have been acquired.
In order to prevent unauthorized use of services as much as possible, the service specific data and/or access rights data may be stored in an encrypted manner. The type of encryption or an encryption key may be chosen in relation to a particular telecommunication system or a particular system operator, for example. It will be appreciated by those skilled in the art that access of the services may be subject to a Personal User Identification (PIN) code or other password or the like.
A telecommunication system can be regarded user friendly whenever services and other features can be approached following a single (access) procedure. With the present invention, this can be provided very easily by storing the service specific data in the memory means of the telecommunication device in accordance with apredetermined user interface. That is to say, to access a particular service the user needs only to know a unique set of key actuations, for example. Dependent on the network to which the device is presently registered, the particular key actuations are converted into commands which can be interpreted by the network.
The conversion is efficiently achieved, in an embodiment of the invention, by storing the service specific data in the form of a matrix type translation table or a translation algorithm. One input parameter of the table or algorithm may be formed by the network identity and another (set) of input parameters may be formed by the user interface commands of a particular type of service, for example.
The user interface can be chosen from the user interface of a particular network of the system, for example the home network of the telecommunication device, a dedicated user interface or any other type of user interface. Note that the different telecommunication devices of a system may operate according to different user interfaces, for example the user interface of their respective home networks.
Service specific data can be stored in the memory means of a telecommunication device over a wired data link, for example a data link coupled to a personal computer, over a radio link, preferably a radio link between a radio communication device and its home network, or another type of data path, such as the keypad means of a communication device, for example a telephone keypad. In the latter case one may think of subscriber numbers to which an arriving telephone call has to be forwarded in case of busy etc. The storage of certain type of data, such as access rights for example, may be limited to a system or network operator or other authority. The service specific data or part thereof may also be stored in memory means which can be separately connected to a telecommunication device, such as a Read Only Memory (ROM) module.
When a telecommunication device registers itself at a network, the network may transfer relevant service specific data to the memory means of the telecommunication device. For example, data relating to access or prefix codes to set up an external, international or other type of call requiring special access codes in the network, for example. Accordingly, in the case of setting up a call using a short number valid for the home network of a subscriber, using the data received from the particular network the telecommunication device can extract the relevant access and/or prefix codes which have to be added to the short number in order to complete the call from the network.
The invention relates also to a telecommunication device, in particular a radio telecommunication device such as a radiotelephone set, for use in a telecommunication system including a plurality of communication networks. The telecommunication device comprises transceiver means, communication control means, and memory means. The memory means are arranged to store data specific to services of the telecommunication system. The telecommunication device is further arranged for exchanging service specific data between the telecommunication device and a communication networkwhen accessing the communication network and/or a particular service thereof.
In an embodiment of the telecommunication device according to the present invention, the memory means are arranged for storing the service specific data in connection with access data identifying a particular network or a particular group of networks. Wherein means are provided for identifying an accessed communication network, which means are operatively connected to the memory means such to retrieve service specific data corresponding to the network or group of networks accessed.
The telecommunication device may comprise display means and user interface control means for displaying service specific user data in accordance with a particular user interface, such to provide a network independent access of the system services. It has proven to be efficient if the memory means are arranged to store the service specific data relative to a particular interface, for example in the form of a translation table or a translation algorithm, such to translate service specific data relative to the user interface into service specific data which can be processed by the accessed network.
The telecommunication device may comprise one or a combination of means for storing service specific data into the memory means received via its transceiver means, via other data input means connectable to the telecommunication device and/or keypad means of the telecommunication device. For receiving memory means separate to the telecommunication device, in another embodiment of the invention, a connector is provided by which the memory means can be releasable connected to the relevant circuitry of the telecommunication device.
The invention further relates to a radio telecommunication system, including a plurality of radio communication networks each comprising radio exchange means, at least one radio base station operatively connected to the radio exchange means and comprising radio transceiver means and communication control means for exchanging information over a radiolink with at least one radio communication device. Such as a cordless radio communication system operating in accordance with the DECT standard. Following the invention a radio communication network of the system comprises means for exchanging service specific data with a radio communication device and memory means for storing retrieved service specific data.
In a yet further embodiment of the radio communication system the data retrieval and memory means are located at the radio exchange means, at the or each base station, and/or at switching means to which the radio communication network connects via the radio exchange means.
In the preferred embodiment of the radio communication system according to the present invention a radio communication network comprises means for providing service specific data to be stored in memory means of a radio communication device, which means are arranged for transmitting service specific data via a radio link established between a base station and a radio communication device, or via data input means connectable to the radio communication device.
The above-mentioned and other features and advantageous of the invention are illustrated in the following description with reference to the enclosed drawings.